Tube bender scale means



May 26, 1959 .*--.1. KowAl..

TUBE BENDER SCALE MEANS Filed Aug. 2, 1957 l||||||||||||||||||x "llll INVENTOR. QORQ'NZJOZUQZ,

TUBE BENDER SCALE lVIEANS Leonard J. Kowal, Prospect Heights, lll., assigner to Imperlilal Brass Manufacturm g Compan a corporation of linois Application ugust 2, 1957, Serial No. 675,950 8 Claims. (Cl. 81-15) This invention relates to a tube bender and in particular to a tube bender having new and improved associated means for determining the proper ldisposition of a tube therein to eiect a desired arrangement of the resultant bent tube.

In making a bend in tubing with a manual tube bender, the operator conventionally determines the approximate location of the desired bend and then associates the tube with the bend forming means of the bender to effect the bend at this location. Should the resultant bend be located somewhat from the desired location, the yieldable nature of the tubing is utilized to compensate for this positional discrepancy. In certain instances, however, as where the end of the bent tube must butt accurately with the end of a fixed tube or element to which it is to be connected, no such positional discrep-ancy may be tolerated. A serious disadvantage of the presently known tube benders is that no means are provided therewith for accurately determining the positioning of the tube relative to the bending means so that the resultant bent tube may be accurately suitably arranged.

The principal object of this invention is to provide a new and improved tube bender having associated means for determining the proper positioning in the bender of the tube to be bent to result accurately in a desired arrangement.

Another object is to provide such a tube bender wherein scale means are carried by the mandrel and handle to indicate a spacing from the mandrel groove for measuring the extension of the tube from the groove.

A further object is to provide such a tube bender wherein the scale means are arranged to indicate the spacing from the center of the mandrel groove opposite the handle.

Still another object is vto provide such a tube bender having scale means correlated with the radius of the mandrel groove indicating the proper positioning of the tube to be bent to compensate for the eect by the curvature of the bend on the dimensioning of the bent tube, thereby to permit accurate. spacing of portions of the tube separated by the bend. i

Other features and advantages of this invention will be apparent from the following description taken in connection with the accompanying drawings wherein:

Fig. 1 is an elevational view of a tube `bender embodying the invention;

Fig. 2 is an end view-thereof;

Fig. 3 is a reduced, fragmentary view thereof and showing a tube therein having a rst 90 angle bend;

Fig. 4 is a reduced, fragmentary view thereof similar to Fig. 3, showing the tube of Fig. 3 as formed with a second 90 bend to space parallel straight portions of the tube at a predetermined distance, the positioning of the tube prior to the provision of the second bend being shown in dotted lines;

Fig. 5 is areduced, fragmentary view thereof showing a first, straight tube associated therewith prior to a bending operation, and the end portion of a second tube positioned a predetermined distance laterally from the ice,I

of the rst tube; and

Fig. 6 is a view similar to that ofFig. 5 but with the first tube bent 90 to butt with the end of the second tube.

In the exemplary embodiment of the invention as disclosed in the drawings, a tube bender is shown to comprise a mandrel 10 and a cooperating shoe member 11. Shoe member 11 is moved relative Ito the mandrel during the tube bending operation by means of a first handle 12 associated with the mandrel and a second handle 13 associ-ated with the shoe member. `Shoe member 11is mounted for movement along a tube bending groove 14 peripherally in mandrel 10, by means of an arm 15 pivotally attached to the side of the mandrel by means of a.

suitable bolt 16. Shoe member 11 is provided with a groove 17 complementary to mandrel groove 14 to define with groove 14 a tube receiving space designated 18, as seen in Fig. 2. Mounted on handle v12 adjacentmandrel 10 to swing about the axis ofthe handle is a suitable hook 19 arranged to encircle a` portion of a tube T to be bent when the tube is placed in the mandrel groove preparatory to a tube bending operation and prevent undesirable.

movement of the tube relative to the mandrel during the bending operation.l

The above describedstructure is more or less conven-` tional in such manually operated tube benders. The instant invention comprehends the provision of suitable scale means associated with such a `tube'bevnder for accurately indicating the positioning of the tubeto be bent so that the tube will have a predetermineddimensioned arrangement subsequent to the provision of onefor more bends therein. For this purpose, three cooperating scale means are provided. A first scale means 20 comprises an angular scale on mandrel 10, indicating angle measurements taken about axis 21 of the mandrel, which axis corresponds to the center of generation of mandrel groove 14. Scale 20 measures this angle from a starting or zero point 22 illustratively-marked 0, as seen in Fig. l, which point is at thev portion of mandrel groove 14 to which tube T is tangent prior to the vformation of a bend therein.

A second scalemeans 23 comprises a `scale extending from a point 24 on mandrel 10 `aligned with the cross-l laterally related portions of the tube. More speciical1yi mark 25 is spaced from starting point 22a distance compensating for the curvature of the tube bend so that when one end of a portion of tube T, the portion having4 a length accurately equal to a desired spacing between the axis of tube T at ment 32 as seen in Fig. 6), isaligned with mark 25 and the tube is then bent the spacing between the plane of the axis of tube T perpendicular to the radius of the mandrel groove at point 22 and said laterally spaced portion or element isaccurately equal 'to that predetermined length. I have found that when mark 25 is spaced from zero point 22 in a direction parallel to the axis of tube T at point 22 `(i.e. in the direction of atangent to groove A14` at point 22) a distanceequalto the circumferential length of the axis of grooveV 14 between Patented `May 26,' 1959 starting point 22 and another portion of tube T (such as a portion 27 as seen in Fig. 4),'

:or another element laterally of tube T (such as an elezero point 22 and point Z4 less the distance between the cross sectional center of tube T in the mandrel groove at zero point 22 and mandrel axis 21, the curvature of the bend is accurately compensated. This increment has been found to be directly proportional to the distance between the cross-sectional center of space 18 and axis 21 andl to be substantially .57 of this distance.

The use of the scale means 20, 23 and 25 permits ready and accurate dimensioning of laterally related portions of tube T and permits accurate butting of the tube end with an associated tubular element. To obtain a bent tube having accurately spaced parallel portions such as 27 and 28 in Fig. 4, the tube bender may be utilized as seen in Figs. 3 and 4. Thus, a first, rightangled bend 26 is provided in tube T as seen in Fig. 3 by moving shoe member 11 through an arc of 90 from zero point 22 as determined by iirst scale means 20. With the tube still in the position of Fig. 3, the desired spacing, designated X, between the axes of right-angularly extending portion 27 and portion 28 at zero point 22 (see Fig. 4) is then measured off from point 24 to the corresponding point on second scale 23, as seen in Fig. 3. In the illustrated embodiment, the desired spacing X isv 6 and, thus, a point 29 is determined on tube T which is aligned with scale marking 6" of scale 23.

Tube T is then moved longitudinally relative to starting point 22 of the mandrel groove to the position shown in dotted lines in Fig. 4 wherein point 29 is aligned with third scale means 25. Tube T is now bent by manipulation of shoe 11 to the desired 90 angle, as determined by scale means 20. The resultant spacing between the axes of portions 27 and 28 of tube T will be accurately the dimension X, in the illustrated example specilcally 6".

In Figs. and 6 the utilization of the tube bender to provide a bend in tube T resulting in the abutment of an end 30 with an end 31 of a second element or tube 32 is shown. In this use of the tube bender, a point 33 is determined which is spaced from tube end 30 a distance equal to the distance designated Y between the end 31 of element 32 and the extension of the axis of the portion 34 of tube T at zero point 22. Point 33 is aligned with mark 25 and the desired 90 bend is formed in the tube by manipulation of shoe 11. As seen in Fig. 6, tube end 30 accurately butts with element end 31 when the formation of bend 35 is completed.

In each case, the additional length of tube T required to compensate for the curvature of the bend is accurately and automatically compounded with the measured length of the tube conforming to the desired spacing to result in a configuration of the bent tube wherein the desired spacing is obtained notwithstanding the inclusion of the bend in the length of tube delining this spacing.

To illustrate the invention two examples of the use of the illustrated embodiment thereof are herein disclosed. It is obvious that other methods of employment may be used depending on the specific spacing and conguration requirements involved.

While I have shown and described certain embodiments of my invention, it is to be understood that it is capable of many modications. Changes, therefore, in the construction and arrangement may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

l. A tube bender comprising: a mandrel provided with a peripheral, annular tube bending groove having a bend starting-point; a shoe member associated with the mandrel to move around the mandrel groove and having a complementary groove delining with the mandrel groove a tube receiving space; a handle secured at one end to the mandrel to extend parallel to a first radius of the groove at right angles to a second radius of the groove through said starting-point; and scale means on the handle to indicate a spacing from the cross-sectional center of the tube receiving space at said first radius, whereby the spacing of the axis of a portion of the tube in said mandrel groove and bent at right angles to a portion of the tube tangent to the groove at the startingpoint from a point on the tube laterally of the handle may be determined.

2. A tube bender comprising: a mandrel provided with a peripheral, annular tube bending groove generated about an axis and having a bend starting-point; a shoe member associated with the mandrel to move around the mandrel groove and having a complementary groove defining with the mandrel groove an annular tube receiving space; a handle secured at one end to the mandrel to extend parallel to a first radius of the groove at right angles to a second radius of the groove through said starting-point; scale means on the handle to indicate a spacing from the tube receiving space at said first radius; and a scale mark on the mandrel spaced from the second radius in the direction of and parallel to the first radius a distance substantially .57 the radius of generation of the groove.

3. A tube bender comprising: a mandrel provided with a peripheral, annular tube bending groove generated about an axis and having a bend starting-point; a shoe member associated with the mandrel to move around the mandrel groove and having a complementary groove deiining with the mandrel groove a tube receiving space; a scale mark on the mandrel spaced from a radius of the groove through the starting-point in the direction of the tangent to the groove at said starting-point and toward the tube receiving space a distance equal to the diterencc between the circumferential length of the central axis of the tube receiving space between the starting-point and a point of the groove from the starting-point and the spacing between said tangent and the axis of groove generation.

4. The tube bender of claim 3 wherein the scale mark is spaced from said radius a distance substantially .57 the distance between said axis of groove generation and the center of said tube receiving space.

5. A tube bender comprising: a mandrel provided with a peripheral, annular tube bending groove having a bend starting-point; a shoe member associated with the mandrel to move around the mandrel groove and having a complementary groove defining with the mandrel groove a tube receiving space; a handle secured at one end to the mandrel to extend parallel to a lirst radius of the groove at right angles to a second radius of the groove through said starting-point; lirst scale means on the handle to indicate a length of tube to be bent extending from a iirst point on the tube; and second scale means to indicate an incremental length of the tube to be bent to Ibe added to the length determined by the first scale means to cause the distance between said point and a plane perpendicular to said second radius and through the center of the tube receiving space at said starting-point to be equal to the length determined by the first scale means when a second point on the tube spaced from said iirst point a distance equal to the sum of said lengths is disposed at said starting-point and the tube is bent 90" to align said first point with the tube receiving space at said first radius.

6. A tube bender comprising: a mandrel provided with a peripheral, annular tube bending groove having a bend starting-point; a shoe member associated With the mandrel to move around the mandrel groove and having a complementary groove defining with the mandrel groove a tube receiving space; a handle secured at one end to the mandrel to extend parallel to a iirst radius of the groove at right angles to a second radius of the groove through said starting-point; and scale means associated with the handle and mandrel to indicate a length of the tube to be bent which will have a desired extension perpendicular to the irst radius away from an end of the length at said starting-point.

anemia' 7. In a tube bender having a mandrel provided with a groove in which a tube is bent by means of a suitable cooperating shoe, means for indicating the proper association of the mandrel and the tube to be bent relative to the groove to have a resultant desired spacing between laterally related portions of the bent tube, comprising: a rst scale means for determining a length of the tube to be bent having a longitudinal extent equal to the desired spacing, and a marking on the mandrel indicating the necessary disposition relative to the mandrel groove of one end of the determined length to compensate for the decrease in the effective spacing between the ends of the determined length resulting from the bending of a portion thereof.

8. In a tube bender having a mandrel provided with a groove in which a tube is bent by means of a suitable cooperating shoe, means for indicating the proper association of the mandrel and the tube to be bent relative to the groove to have a resultant desired spacing between laterally related portions of the bent tube, comprising: a

first marking on the mandrel indicating the starting-point of the bend; and a second marking correlated with the first marking indicating the necessary disposition relative to the mandrel groove of one end of a length of the tube to be bent to compensate for the decrease in the eiective spacing between the ends of the length resulting from the bending of a portion thereof.

References Cited in the le of this patent 

